Process of making dialkyl-barbituric acids.



e nrran srarns Parana orrron.

MAX ENGELMANN, OF, ELBER-FELD, GER-MANY, ASSIGNOR TO FARBEN- FABRIKEN OF ELBERFELD (30., OF NEW YORK, N. Y., A CORPORA- TION OF NEKV YORK.

Specification of Letters Patent.

Patented Jan. 9, 1906.

Application filed October 16, 1905. Serial No, 283,017.

ing Dialkyl-Barbituric Acids; and I do here by declare the following to be an exact and clear description of my invention.

My inventiop relates to a new and valuable process-for the production of dialkyl-barbiturie acids (2-4-(i-trioxy-5-dialkylpyrimidinsfi having the following general formula:

I (R meaning an alky\l radical,) which bodies possess valuable therapeutic, especially soporlfic, properties.

e process consistsln heating with acids the 2 thio 4 imino-5-dialkyl-G-oxypyrimidi ns having the following general formula:

l-lH- (/O R sze c na-e'zru-i By this process the sulfur and the imino 1 group are eliminated an d replaced by oxygen, dialkyl-barbituric acids being formed.

The 2 thio 4 imino-5-dialkyl6-0Xypyrimidins are obtained, as is known, by condensare heated in an autoclave for iive (5) hours i to onehundred and fifty degrees (150) centigrade with eighty (80) parts, by weight, of fuming hydrochloric acid. After cooling the diethyl-barbituric acid (2-4-6-trioxy-5-diethylpyrimidin) which has separated is filtered of? and purified by recrystallization from water.

Example 11: Five (5) parts, by weight, of 2- thio-4-imino-5-dipropyl-6-oxypyrimidin are heated at a reflux-condenser for twenty (20) hours with one hundred (100) parts, by weight, of a sulfuric-acid solution containing forty per cent. of sulfuric acid. After cooling the dipropylbarbituric acid which has separated in crystals is purified by recrystallization.

The process can alsobe carried out with other of the above-mentioned pyrimidin derivatives, such as Z-thio-4-iminc-5-dimethylfi-oxypyrimidin, &c., or with other acids.

Having now described my invention and in what manner the same is to be performed, what I claim as new, and desire to secure by Letters Patent, is-

1. The process for the production of dialkylbarbituric acids having the above-given general formula, which process consists in heating 2 thio 4 imino-5-dialkyl-S-oxypyrimiclins with acids, substantially ,as hereinbefore described.

2; The process for the production of diethylbarbituric acid, which process consists in heating 2-thi0-4 iinino-5-diethyl-o-oxypyrimidin with acids, substantially as hereinbefore described.

In testimony whereof I have signed my name in the presence of two subscribing witnesses.

MAX ENGELMANN.

Witnesses Orro Home, J. A. RIrrnRsnAUs. 

